*Crossing the Gender Barrier
Though dude had been applied to women as early as the mid-70's, its use came to a tipping point somewhere in the mid-80's. Attempts to establish dudette as the feminine form utterly failed (the original term for a fine-looking woman among Hawaiian surfers, wahine, never established itself either) and it is is now a fact that dude, at least in the prescriptive sense, can refer to both men and women. Perhaps the first mainstream display of this usage appeared in the movie Less Than Zero, in which there is a scene where a young woman defiantly tells her mother, "No way, dude!". Indeed, even American Heritage Dictionary recognizes this in its dude definition 3.b., that "dudes" are "Persons of either sex".

http://en.wikipedia.org/wiki/Dude

Ну что, дура?